Speed control system for laundry appliance



June 13, 1967 T. R. SMITH SPEED CONTROL SYSTEM FOR LAUNDRY APPLIANCE Filed Dec. 6, 1965 2 Sheets-Sheet 1 v E'gii Wzw AMM June 13, 1967 T. R. SMITH 3,324,691

SPEED CONTROL SYSTEM FOR LAUNDRY APPLIANCE Filed Dec. 6, 1965 v 2 Sheets-Sheet 2 United States Patent C) 3,324,691 SPEED CONTROL SYSTEM FOR LAUNDRY APPLIANCE Thomas R. Snfith, Newton, Iowa, assignor to The Maytag Company, Newton, Iowa, a corporation of Delaware Filed Dec. 6, 1965, Ser. No. 511,719 7 Claims. (Cl. 6824) This invention relates to a laundry appliance and more specifically to a combination washer-drier having a drive system and energy absorption means cooperable for effecting rotation of the fabric container at a plurality of speeds including a relatively fast extraction speed commensurate with the amount of unbalanced loading of the container.

The problem of unbalanced loading is encountered in laundry devices because of the tendency of the fabrics to become arranged in an uneven pattern around the inner periphery of the rotatable container as the container is accelerated toward extraction speeds. This unbalanced loading causes severe vibrations as the speed of the container increases. It is essential, therefore, that means he provided for overcoming or preventing the vibrations caused by the unbalanced loading at high rotational speeds. In prior art devices a number of varied approaches have been used in attempts to avoid the problem of excessive unbalance-caused vibrations. For example, in some combination washer-driers the speed of the rotating container is decreased from an extraction speed to a tumble speed upon encountering an unbalanced condition. Other devices, upon sensing an unbalanced condition, prevent further acceleration and hold at the particular speed at which a predetermined unbalance or vibration is sensed or institute cyclical acceleration and deceleration in an attempt to maintain fluid extraction.

In order to actieve a satisfactory extraction operation, it is important that the fabrics be as evenly distributed as possible about the inner periphery of the container and then to maintain the extraction speed at as high a level as vibrations will permit. It is important that extraction be maintained at as high a speed as possible since the continued removal of fluid from the fabrics will tend to decrease the amount of unbalance and thereby permit somewhat further increases in extraction speed.

It is therefore an object of this invention to provide a drive system and energy absorption system cooperable in a combination washer-drier to achieve improved fluid extraction.

It is a further object of the instant invention to provide an improved combination washer-drier having a vibration control system and means for controlling torque input to achieve improved operation of the device during the extraction portion of the cycle.

It is a further object of the present invention to provide a combination washer-drier having a limited torque input during the extraction operation and responsive to unbalanced loading conditions to effect rotation of the container at a speed commensurate with unbalanced loading therein.

It is a further object of the present invention to provide a belt-driven combination washer-drier having selectively energizable means for conditioning the drive system for limited torque input during a portion of the cycle of operations.

It is a further object of the present invention to provide a combination washer-drier having positive drive characteristics at relatively slow speeds and torque-limiting slipping-belt characteristics at relatively fast speeds and further including energy absorption means responsive to unbalance-caused vibrations to effect rotation of the 3,324,691 Patented June 13, 1957 container at speeds commensurate with unbalanced loading.

The present invention achieves the above objectives in a combination washer-drier having a belt drive system responsive to selectively engageable idler means for effecting a positive drive with no belt slippage during low speeds and for effecting a slipping-belt drive during high speeds to achieve a predetermined limited torque input. Damper means are provided to absorb energy as the container vibrates or oscillates responsive to unbalanced loading. It may therefore be seen that with a given, or predetermined, torque input and a means for absorbing a portion of the input energy, responsive to unbalanced loading, the drive means will be limited to driving the rotatable container at a speed commensurate with the amount of unbalanced loading.

Operation of the device and further objects and advantages thereof will become evident as the description proceeds and from an examination of the accompanying drawings which illustrate a preferred embodiment of the invention and in which similar numerals refer to similar parts throughout the several views, wherein:

FIGURE 1 is a rear elevational view showing a combination washer-drier partially in section to expose a portion of the drive system and damper system of the instant invention; and

FIGURE 2 is a side elevational view showing additional details of the combination washer-drier of FIGURE 1.

Referring now to the accompanying drawings in detail, it will be seen that the combination washer-drier shown in these drawings and comprising an embodiment of the instant invention includes a substantially flat surfaced base frame 10 mounted on a plurality of legs 11. Mounted upon base frame 10 is a pair of support members 13 and 14 which are welded, or securely fixed in some suitable manner, to the base frame 1th to form the two major supports for the washer-drier unit illustrated in the accompanying figures.

As apparent from an inspection of FIGURES 1 and 2, support members 13 and 14 have a channel cross section and a substantially triangular elevational configuration with the apex of these members receiving pivot pins 16 and 17. Pivot pins 16 and 17 are journaled in bearings 18 and 19 retained by brackets 21 and 22, respectively, to form a two-point support for tub 24. This allows the tub 24, which is fastened to brackets 21 and 22, to oscillate back and forth on pins 16 and 17 in an arcuate movement responsive to various forces generated within tub 24.

Tub 24 is normally maintained in an upright position on pins 16 and 17 by the two centering springs 25, each connected between base 10 and tub 24 by the spring anchor brackets 26 and 27 fastened to the base 10 and tub 24, respectively. Damper bracket 28 is attached to the tub 24 to form the support for the damper leaf spring 29 as best shown in FIGURE 1. Damper pad 31 is carried in a ball and socket joint at the end of damper spring 29. Base frame 10 is provided with an upstanding damper plate 32 frictionally engaged by the damper pad 31. The energy imparted to tub 24 causes tub 24 to oscillate on the supporting pivot pins 16 and 17 so that the energy is absorbed and dissipated by the relatively movable, frictionally engaged damper pad 31 and damper plate 32.

The tub or casing 24 includes a generally cylindrical side wall 71, a pair of spaced rear walls 72 and 73, and a front wall 74. The front and outer rear walls 74 and 72, respectively, are connected to cylindrical side wall 71 by means of the encompassing flanged hoop-like members 76 while the partition wall 73 positioned between walls 72 and 74 is secured, as by welding, to side wall 71. It will 3 be seen from an inspection of FIGURE 2 that the spaced rear walls 72 and 73 support the tub bearing assembly, generally indicated by the reference numeral 80.

The bearing assembly 80 includes a spacer hub 81 located between and abutting the rear walls 72 and 73, and a tubular clamp member 82 located concentrically within hub 81. Clamp member 82 is formed with a shoulder 85 at one end thereof and has a threaded portion 84 at the other end thereof for receiving clamp nut 83 which, when tightened on member 82, produces a rigid support with respect to tub 24 for two bearings (not shown), with one located adjacent each of Walls 72 and 73 within hub 81 for supporting drive shaft 89. The rear end of drive shaft 89 is rigidly connected to the large drive pulley 91 whereas its front end is joined with hub 94 of the fabric container 95. Container 95 includes a perforate rear wall 96 rigidly aflixed to and cooperating with spiderlike member 97 to form a double cone support connected to the hub 94 for providing a rigid support for the fabric container 95 on drive shaft 89. A sealing member 100 is biased against the rear surface of this revoluble hub structure 94 to prevent water in tub 24 from entering bearing assembly 80. As apparent from FIGURE 2, container 95 also includes a perforate cylindrical side wall 104 and clothes elevating vanes 105. Side wall 164 merges into the short front wall 166 and joins flanged rear wall 96 in an overlapping relationship to form a protruding flange 108 spaced from wall 73 and cooperable with wall 73 to form an effective air barrier for preventing the short circuiting of heated air around the rear peripheral edge of container 95.

Front wall 74 of tub 24 also includes a circular loading opening 117 encircled by one end of the bellows seal 118. This seal 118 in turn has its opposite end fastened to a similar opening formed in the cabinet 119. Sealing member 118 includes a number of convolutions 120 permitting movement of tub 24 relative to cabinet 119. A rectangular door 121 hinged on cabinet 119 carries a transparent glass window 122 having a cylindrical portion extending rearwardly through the bellows seal 118 for peripheral enegagement with a flexible annular sealing lip 124. This arrangement effectively seals the unit against fluid leakage while enabling the operator of the machine to observe operations taking place within tub 24 during the washing and drying processes.

Though not shown, the instant combination includes means for providing washing fluids to the tub 24 and also includes means for supplying heat to tub 24 for the drying operation. A pulley 139'is driven for rotating an impeller (not shown) which forms a part of the blower-condenser unit capable of moving air through tub 24, scrubbing lint from this air, and condensing moisture from hot vapors formed within tub 24 during the driving operation.

Tub 24 further includes a lower recessed portion in the form of a sump 149 communicating with a drain pump 150. Sump 149 receives the washing fluids from casing 24 and also receives, from the blower-condenser compartment, the condensing fluids and condensate along with lint removed from the air entering the blower-condenser unit. The fluids and lint entering sump 149 are discharged through pump 150 to an external drain (not shown). A valve 154, controlled by solenoid 155, is positioned between pump 150 and the external drain to control the periods of time fluids are discharged to the external drain. Pump 150 is driven during washing operations by a pulley at 156; however, solenoid 155 is de-energized during the washing operations to maintain valve 154 closed and fluids within the tub 24.

More specific details of construction of the washerdrier combination unit as hereinabove described may be found in US. Patent 2,986,917 issued to T. R. Smith on June 6, 1961 and assigned to the assignee of the instant invention.

As best seen in FIGURE 1, container 95 is driven through pulley 91 and through the main drive belt 160 i which is in turn driven by a multispeed power source 161. Power source 161 in this embodiment is operable for providing a pair of relatively low speeds for rotating container at a tumble speed and at a distribution speed and also operable for driving container 95 at a relatively high extraction speed.

In the instant application a preferred embodiment of the three-speed power source 161 comprises a two-speed reversible motor 163 operable for driving a directional responsive split pulley 164. When pulley 164 is driven in a first direction container 95 is rotated at a first speed and when driven in a second direction at the same input speed container 95 is driven at a second speed. This difference in output speeds is achieved through the variable speed characteristics of this split pulley 164. As best seen in FIGURE 2, the pulley 164 is shown in a position with the pulley halves 165, 166 separated to permit the main drive belt 160 to ride very low in the V groove of the pulley for providing a first relatively high ratio speed reduction to effect rotation of container 95 at a tumble speed. Upon reversal of the rotation of motor 163, the pulley halves 165, 166 operate to reduce the spacing therebetween and to cause main drive belt 160 to ride higher in the V groove and thereby effect a somewhat smaller speed reduction ratio for driving container 95 at a distribution speed slightly greater than the tumble speed. The split, variable speed pulley 164 may be of a construction having a threaded connection between the shaft 168 and the pulley halves 165, 166 and responsive to a reversal of rotation for changing spacing between the halves. Stops or limiting means for locating or limiting movement of the pulley halves 165, 166 to each of the two desired speed reduction positions may be provided.

As previously indicated, the power source 161 in the instant embodiment includes a two-speed reversible motor 163 such as a two-pole, twelve-pole arrangement. The pulley ratios have been established to eifect rotation of container 95 at approximately 300 rpm. when the motor 163 is operating in its higher speed of approximately 3600 -r.p.m. and to operate or rotate container 95 at tumble and distribution speeds of 50 and 60 r.p.m., respectively, when operating in its lower speed.

As best shown in FIGURE 2, the motor 163 is provided with shaft extensions at both endsfor driving a plurality of components included in the combination washer-drier of the instant invention. The shaft 169, extending from the left end of the two-speed motor 163, supports an auxiliary pulley 170 drivingly coupled by a stretchable belt 171 to a pump-mounted pulley 156 for rotating the pump 150. The drain pump will therefore be driven during each period of operation of motor 163 but will be operative for pumping fluid from tub 24 only during those periods when the solenoid is energized for opening valve 154.

The shaft 168, extending from the right end of the motor as viewed in FIGURE 2, carries a pair of pulleys 173, 164 mounted thereon. The first pulley 173, adjacent the right end of the motor, is fixed to the motor shaft 168 and drives a blower belt 174 for rotating blower pulley 139. The second pulley is the split variable-speed pulley 164 for driving the main drive belt and T0- tating container 95.

The motor 163 is adjustably and pivotally mounted on tub 24 so as to provide for proper tension in the blower and main drive belts 174 and 160. The motor 163 is secured to an inverted U-shaped bracket 175 with a pair of adjustable clamps 176. The invertedU-shaped bracket is formed with a pair of upturned tabs 178 for receiving a pin 179 supported by the flange 180 of an adjustably mounted bracket 181. Bracket 181 is in turn provided with a plurality of slots 183 to receive screw members 1 84 for attaching the adjustable bracket 1 81 to a plurality of brackets 185'secured to tub wall 71.

The motor 163 is biased in a clockwise direction about the pin 179, as viewed in FIGURE 1, by a coil spring 186 connected between the U-shaped bracket 181 and a notched bracket 188 fixed to the outer wall of tub member 24 as best seen in FIGURE 1.

Whether the main drive belt 160 is conditioned for a positive drive or for a slipping-belt drive is determined -by a belt tension control means in the form of a selectively engageable idler pulley arrangement 189 as best shown in FIGURE 1. An idler pulley 190 is rotatably mounted on a pivot arm 191, in turn pivotally mounted on a bracket 193 attached to back wall 72. A biasing spring 194 is attached between the pivot arm 191 and an anchor bracket 195 attached to the back wall 72 for normally biasing the idler pulley 190 into engagement with the main drive beit 160 and effecting a condition of positive drive through the main drive belt 160'. Adjustment may be provided at the anchor bracket to provide for varying the biasing effect of the spring. Also connected to the pivot arm for effecting movement of the pivot arm 191 and idler pulley 190 in a clockwise direction is a selectively energizable solenoid 196 mounted on back panel 72. It may thus be seen that the idler pulley 190 is normally engaged through the biasing action of the spring 194 and is selectively movable to a disengaged position by operation of the solenoid 196.

The adjustable bracket 181 and adjustable spring 186 permit the motor 163 to be positioned so that the idler pulley 199 is operable for effecting a condition of posi tive torque transmission between the motor 163 and the main drive pulley 91. Upon movement of the idler pulley 190 to a disengaged position, a condition of limited torque transmission is established through the main drive belt 160 so that upon reaching a predetermined torque the belt will slip and thereby function as a torque limiting device.

The combination washer-drier embodying the instant invention is operable through a conventional washing and drying cycle of operations including a relatively low speed tumble dry operation, an intermediate speed distribution operation and a relatively fast extraction speed operation. This cycle of operations is controlled by a timing control mechanism (not shown) which is operable for sequentially energizing and de-energizing the various electrically operated or controlled components to provide the above identified operations as well as other supplemental or auxiliary operations.

It may, therefore, be seen that the instant invention cooperates with the timing control mechanism to provide a plurality of speeds and operations comprising the above mentioned Washing and drying cycle of operations. The first of the required speeds, that of a tumbling speed, may be achieved by energizing the motor 163 in its low speed condition of operation in a counter-clockwise direction of rotation as viewed in FIGURE 1 and with the idler pulley 190 engaged with the main drive belt 160. Under these conditions of energization the motor 163 will be operating at a low speed of approximately 600 r.p.m., the split pulley 164 will be in its separated position, and the idler pulley 190 will be engaged to effect rotation of container 95 under conditions of positive torque transmission at approximately 50 r.p.m.

Upon completion of tumbling operation, and following a short pause, the timing control mechanism will effect low speed rotation of the drive motor 163 in a clockwise direction while maintaining the idler solenoid 196 in the de-energized position. This clockwise rotation of the motor 163 will efifect a movement of the pulley halves 165, 166 together and establish a second, lower, speed reduction ratio for effecting rotation of container 95 at a speed slightly above the tumble speed. This slightly higher speed will effect distribution of the fabrics around the inner periphery of container 95 prior to, and preparatory to, proceeding into a high speed extraction operation.

After a predetermined period of time for operation at the distribution speed the motor 163 is energized for high speed spin in the clockwise direction and the solenoid 196 is energized to disengage the idler pulley 190. Disengagement of the idler pulley 190 establishes a condition of limited torque transmission between the motor 163 and the main drive pulley 91, Under normal operating conditions, and with relatively low unbalance loading, basket will gradually accelerate to its normal extraction speed of approximately 300 r.p.m. If, however, unusual or excessive unbalance loading conditions exist within container 95 an insufiicient amount of torque is available to accelerate container 95 to the 300 r.p.m. The unbalanced forces cause drum 24 to oscillate in an arcuate path rela tive to pivot pins 16 and 17 so that the frictional damper system absorbs and dissipates a portion of the torque input. Since there is a limited torque input, and since part of this energy is absorbed by the damping system during oscillation of the container, there will remain inadequate torque to further accelerate the container 95 above that speed at which the unbalance-caused movement becomes excessive.

The container, however, will continue to rotate at less than the normal extraction speed dependent upon the net accelerating torque and fluids will continue to be removed from the fabrics. As the fluids are removed from the fabrics, the forces of the rotating unbalance tends to become less. Therefore, the energy absorbed by the damping system decreases as the movement caused by the unbalance decreases. It is thus seen that the portion of the torque input that is available to accelerate the container 95 is commensurate with the amount of unbalance forces and therefore the spin speed is commensurate with the amount of unbalanced loading. In other words the maximum extraction speed at any moment is a function of the torque input and the energy absorbed by the damping system when excessively unbalanced loads are rotated.

This invention therefore provides a unique drive system and energy absorption system especially advantageous in a combination washer-drier for achieving optimum fluid extraction under conditions of unbalanced loading. The drive means and energy absorption means cooperate to effect operation at a speed at which vibrations are not excessive or objectionable,

In the drawings and specification, there has been set forth a preferred embodiment of the invention, and although specific terms are employed, these are used in a generic and descriptive sense only, and not for purposes of limitation. Changes in form and the proportion of parts, as well as the substitution of equivalents are contemplated, as circumstances may suggest or render expedient, without departing from the spirit or scope of this invention as further defined in the following claims.

I claim:

1. In a laundry apparatus, the combination comprising: fabric container means; base means; means mounting said container means for rotation about an axis and for vibratory movement relative to said base means; means for driving said container means at a plurality of rotational speeds including a relatively low speed and a relatively high speed, said drive means including a power source and a belt means drivingly connected between said power source and said container means; belt tension control means for selectively effecting a positive drive connection during said low speed operation and efiiecting a slippingbelt drive connection for transmitting a predetermined limited torque input during said high speed operation; and damper means responsive to vibratory movement of said container means for absorbing and dissipating energy of unbalance-caused vibrations during said high speed operation whereby a portion of the input torque is absorbed and rotation of said container means is limited to a speed less than said relatively high speed commensurate with the severity of said unbalance-caused vibrations.

2. In a laundry apparatus as defined by claim 1 and wherein said driving means comprises a two-speed motor and a variable speed pulley operable for eflecting an additional relatively slow speed to provide three selective speeds including a first relatively low speed through said positive drive connection for tumbling the fabrics in said container means, a second relatively low speed through said positive drive connection for distributing the fabrics about the inner periphery of said container means, and a relatively high speed through said slipping-belt drive connection for extracting fluids from the fabrics within said container means.

3. In a laundry apparatus as defined by claim 1 and wherein said driving means includes a two-speed reversible motor and a directional-responsive split pulley operable for efiecting an additional speed to provide three selective rotational speeds of said container means including a first relatively low speed with said motor operating in a first direction for tumbling the fabrics within said container means, a second relatively low speed with said motor operating in a second direction for distributing the fabrics about the inner periphery of said container means, and a relatively high speed through said slipping-belt drive connection and with said motor operating in said second direction for extracting fluids from fabrics contained within said container means.

4. In a laundry apparatus as defined by claim 1 and wherein said belt tension control means includes idler pulley means engageable with said belt means and further includes means for controlling engagement of said idler pulley means with said belt means to selectively efiect said positive drive connection and said slipping-belt drive connection.

5. In a laundry apparatus as defined by claim 4 and wherein said engagement control means includes biasing means for maintaining said idler pulley means in a first position and further includes selectively operable actuation means for overcoming said biasing means and moving said idler pulley means to a second position.

6. In a laundry apparatus as defined by claim 4 and wherein said engagement control means includes biasing means for maintaining said idler pulley means in said positive drive connection and further includes actuation means operable for overcoming said biasing means to shift said idler pulley into said slipping-belt connection.

7. In a laundry apparatus as defined by claim 6 and wherein said biasing means comprises a spring means and said actuation means comprises a solenoid means energizable upon operation of said drive means for said relative high speed.

References Cited UNITED STATES PATENTS 3,029,624 4/1962 Fogt 74-242 X 3,101,625 8/1963 Horvath 6824 X 3,188,838 6/1965 Hubbard 6824 X FOREIGN PATENTS 1,287,987 2/1962 France.

WILLIAM I. PRICE, Primary Examiner. 

1. IN A LAUNDRY APPARATUS, THE COMBINATION COMPRISING: FABRIC CONTAINER MEANS; BASE MEANS; MEANS MOUNTING SAID CONTAINER MEANS FOR ROTATION ABOUT AN AXIS AND FOR VIBRATORY MOVEMENT RELATIVE TO SAID BASE MEANS; MEANS FOR DRIVING SAID CONTAINER MEANS AT A PLURALITY OF ROTATIONAL SPEED INCLUDING A RELATIVELY LOW SPEED AND A RELATIVELY HIGH SPEED, AND DRIVE MEANS INCLUDING A POWER SOURCE AND A BELT MEANS DRIVINGLY CONNECTED BETWEEN SAID POWER SOURCE AND SAID CONTAINER MEANS; BELT TENSION CONTROL MEANS FOR SELECTIVELY EFFECTING A POSITIVE DRIVE CONNECTION DURING SAID LOW SPEED OPERATION AND EFFECTING A SLIPPINGBELT DRIVE CONNECTION FOR TRANSMITTING A PREDETERMINED LIMITED TORQUE INPUT DURING SAID HIGH SPEED OPERATION; AND DAMPER MEANS RESPONSIVE TO VIBRATORY MOVEMENT OF SAID CONTAINER MEANS FOR ABSORBING AND DISSIPATING ENERGY OF UNBALANCE-CAUSED VIBRATION DURING SAID HIGH SPEED OPERATION WHERBY A PORTION OF THE INPUT TORQUE IS ABSORBED AND ROTATION OF SAID CONTAINER MEANS IS LIMITED TO A SPEED LESS THAN SAID RELATIVELY HIGH SPEED COMMENSURATE WITH THE SEVERITY OF SAID UNBALANCED-CAUSED VIBRATIONS. 